New ion-optical operating modes of the BigRIPS and ZeroDegree spectrometer for the production and separation of high-quality rare isotopes beams and high-resolution spectrometer experiments

Abstract

BigRIPS is a powerful two-stage in-flight separator for the research with exotic nuclei studied in frontier experiments since more than a decade. The ion-optical system is very versatile due to the multi-stage structure of BigRIPS combined with the ZeroDegree spectrometer or the Superconducting Ring Cyclotron (SRC). Various optical modes can be flexibly realized according to the purpose of experiments. Two categories of developments are presented here. One is a new operating mode of BigRIPS aiming at higher ion-optical resolving power. BigRIPS itself has a two-stage structure. Spatial isotope separation is made at both the first and second stages. In the standard operating mode of BigRIPS, at the second stage the two spatial separations with energy degraders are subtractive in their resolving powers. Here, we present the additive mode. With the resulting increased spatial separation power, the isotopic background can be substantially reduced. Higher ion-optical resolving powers of the first and second BigRIPS degrader stages are also investigated with the goals to reduce further the background and to yield access to new isotopes of heavier elements. The other development is a dispersion-matched system with BigRIPS for high-resolution spectrometer experiments. The BigRIPS and ZeroDegree spectrometer are presently two independent, coupled achromatic systems. A new dispersion-matched mode of BigRIPS and ZeroDegree will enable novel experiments. For high-resolution spectroscopy experiments with high-intensity light projectiles, SRC and BigRIPS can be operated as a dispersion-matched system. The described different ion-optical developments are a base for a new category of experiments exploring exotic nuclei and mesic atoms. Characteristic future experiments with these new ion-optical developments are exemplified in this report.